A Case of Iatrogenic Kaposi's Sarcoma Relapsed with Worsening of the General Condition with Pneumonia and Urinary Tract Infection

Abstract

A 75-year-old woman presented with purple-red nodules on the left lower thigh about half a year before her first visit. More similar tumors gradually appeared and spread to her left lower thigh. In the skin biopsy, spindle-shaped tumor cells proliferated and formed lumens throughout the dermis, and the lumens were full of red blood cells. Some red blood cells leaked outside the blood vessel. On immunostaining, the tumor cells were positive for CD31 in the cell membrane and LANA-1 in the nucleus ; they were diagnosed as Kaposi's sarcoma. One and a half years before her first visit, she developed optic neuromyelitis and after steroid pulse treatment, she started taking oral prednisolone (PSL) 50 mg and tacrolimus. At the first visit to our department, she was taking 10 mg of PSL and 4 mg of tacrolimus. She was believed to be immunosuppressed because she was taking oral PSL and tacrolimus for a long time. In addition, both HIV antigen and antibody were negative, and the possibility of iatrogenic Kaposi's sarcoma was high. Chest computed tomography (CT) revealed a pulmonary nodular shadow ; further, upper and lower gastrointestinal endoscopy and bronchoscopy showed disseminated lesions in the stomach and the bronchus. All these lesions were considered lesions of Kaposi's sarcoma. After the diagnosis, tacrolimus was discontinued, and PSL was gradually reduced from 10 mg/day to 7 mg/day in 3 months ; subcutaneous nodules of her lower leg were reduced in size in 3 months. However, after the patient developed pneumonia and urinary tract infection, her general condition deteriorated. The subcutaneous tumors increased and spread to both the legs, and pulmonary nodular shadows increased on the chest CT simultaneously. About 2 months after the development of pneumonia and urinary tract infection, she died because of respiratory failure. The condition of patients with iatrogenic Kaposi's sarcoma is usually improved by reduction or withdrawal of the immunosuppressive drugs. Although this patient's condition temporarily improved by withdrawal and reduction of tacrolimus and PSL, respectively, along with the worsening of the general condition, Kaposi's sarcoma lesions exacerbated simultaneously.